David Kirby with the Huffington Post recently mentioned being “revolted” by what he learned when researching his new book “Animal Factory”: what revolted Kirby was the discovery that cattle are fattened on chicken manure. We were revolted as well until we researched Kirby’s claim.

Now we’re appalled.

Because not only are many of America’s cattle herds fed chicken manure, they’re also fed euthanized dogs and cats, dead skunks, rats, and raccoons found on U.S. highways; as well as heavy metals from pet and cattle ID tags, surgical pins, needles, plastic and Styrofoam, plastic insecticide patches, green plastic bags containing dead pets from veterinarians, and more. All of these items are pulverized and made into dry feed through a process called rendering.

Every time you and I eat a steak or hamburger, we may also be eating the pulverized remains of the possum we hit on the road last week, or Aunt Harriet’s poodle, or our neighbor’s cat that was put to sleep and fed to the slaughtered cow we had for dinner. And because they don’t strip euthanized animals of flea collars and pet ID tags before rendering, we’re also eating ground up metal and chemicals as well.

The process of rendering has been around for centuries, and was initially performed to make soap and candles. Simply put, rendering is what occurs when meat is boiled in water to separate fat and lard. But on today’s industrial level, rendering converts animal carcasses — tissue, bones, internal organs, hooves, blood, feathers, and hair, — into dry meat by-products that are sold as animal feed.

Modern rendering today involves tossing animal carcasses into huge steam jacketed vessels; the carcasses are then ground, and cooked at temperatures of between 220 degrees and 270 degrees for twenty minutes to an hour to release fat and moisture.

The tallow is removed and is the source of animal fat in most pet foods; the rest is percolated until fat is pressed out of the solids into “dry-rendered tankage”. The resulting product is ground further and then separated into fat, water and fine solids by stages of centrifuging. The solids are pressed and dried and made into animal feed, commonly known as meat by-products and bone meal.

In a 1997 article in US NEWS & WORLD REPORT, we learned that animal-feed manufacturers and farmers were also experimenting with dehydrated food garbage — fats emptied from restaurant fryers and grease traps, cement-kiln dust, newsprint and cardboard derived from plant cellulose, and even human sewage sludge.

We can’t help but wonder how much more refined and creative the dehydrated food garbage business has become in thirteen years. While most food activists are concerned with genetically modified corn meal in our cattle feed, the situation is closer to the science fiction filmSoylent Green.

Last February, Spencer Hunt with THE COLUMBUS DISPATCH reported on the shrinking number of rendering plants in the country. Hunt claimed big businesses have centralized operations and consolidated by buying out smaller ones.

The U.S. has more than 200 working plants, 38 of which are owned by one company, says Hunt. That means dead carcasses rot even longer before they’re trucked to the nearest plant to be boiled and chopped up into feed.

Tom Cook, president of the National Renderers Association in Arlington, Va., says the number of rendering plants are diminishing because disease fears have led many pet-food and livestock-feed manufacturers to reject proteins rendered from dead animals. Do you believe him? I don’t.

As long as there’s a profit to made from recycling dead bodies into animal feed and pet food, you can be sure it will be business as usual. If the number of rendering plants have decreased, it’s because the rendering business is consolidating.

Because these rendering plants serve as huge toxic waste dumps used to recycle animals into animal feed, what we currently have is a food system based on cannibalism, where cattle eat cattle, chickens eat chickens, and pigs eat pigs. Cattle are herbivorous creatures meant to eat grasses. And chickens naturally eat grass, weeds, bugs, and worms.